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JFFS2 garbage collection daemon in Kernel 2.6.14



Hi,

I've been in the process of implementing Linux kernel 2.6 (specifically now
2.6.14) on an IXP425 development board.

When the kernel boosts, it will mount the jffs2 flash partition and start to
initialize `init`, then I start getting a soft lock errors like:

   BUG: soft lockup detected on CPU#0!

Alot of these are caused by some custom software that is executed on the
filesyste that was written for kernel 2.4.  Once I stop that from executing on
bootup, my other problem lies with the JFFS2 garbage collection daemon that is
initialized as a kernel thread/process ./fs/jffs2/background.c, line 75.

I've commented out the line so the JFFS2 garbage collection daemon doesnt
initialize at all as that kernel process/thread and I have a stable filesystem
as far as I can tell.

I was curious though; I know stopped the error from coming up, but I want to
know if not having the garbage collection daemon running is a bad idea?  From a
forum post back in August 2000 (http://mhonarc.axis.se/jffs-dev/msg00123.html)
it was said that it's not that big of deal b/c, at most, instead of keeping the
filesystem constantly in-check and fresh, if/when the filesystem runs out of
space, the garbage collection mechanism will kick in anyway.

Is that still safe to assume now?  Or am I doing something wrong when
implementing the JFFS2 filesystem under 2.6?  Or maybe it was just the older
software that was doing it all along.  

Any information that can be offered, I'd greatly appreciate it.  I know how well
enough how that garbage collection daemon to really fine tune my trouble-shooting.

NOTE:  below is my output with the soft lock error for jffs2_gcd_mtd2.

Thank you,

Adam
-----------------
# mount / -o remount,rw
BUG: soft lockup detected on CPU#0!

Pid: 59, comm:       jffs2_gcd_mtd2
CPU: 0
PC is at release_console_sem+0x15c/0x210
LR is at 0x238e9e5
pc : [<c0034ea0>]    lr : [<0238e9e5>]    Not tainted
sp : c3ec3d24  ip : c3ec3d24  fp : c3ec3d44
r10: c3cb9fa8  r9 : 60000013  r8 : ffffc000
r7 : c01bef68  r6 : 60000013  r5 : 0238e9e5  r4 : 0238e9e5
r3 : c01c7960  r2 : ffffffff  r1 : 0238e9e5  r0 : 0238e9e5
Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  Segment user
Control: 39FF  Table: 03EB8000  DAC: 00000015
[<c0020690>] (show_regs+0x0/0x4c) from [<c004e888>] (softlockup_tick+0x64/0x7c)
 r4 = C3EC3CDC
[<c004e824>] (softlockup_tick+0x0/0x7c) from [<c003bf3c>] (do_timer+0x414/0x490)
 r4 = 00000001
[<c003bb28>] (do_timer+0x0/0x490) from [<c00237d8>] (timer_tick+0xb4/0xe4)
[<c0023724>] (timer_tick+0x0/0xe4) from [<c0029ac8>] (ixp4xx_timer_interrupt+0x5
0/0x90)
 r6 = C3EC3CDC  r5 = C01FB5A0  r4 = C01F6074
[<c0029a78>] (ixp4xx_timer_interrupt+0x0/0x90) from [<c001f7f8>] (__do_irq+0x4c/
0x88)
 r6 = 00000000  r5 = 00000000  r4 = C01BE2D0
[<c001f7ac>] (__do_irq+0x0/0x88) from [<c001fa40>] (do_level_IRQ+0x6c/0xbc)
 r8 = C3EC3CDC  r7 = C01BEF68  r6 = C3EC3CDC  r5 = 00000005
 r4 = C01F5588
[<c001f9d4>] (do_level_IRQ+0x0/0xbc) from [<c001fadc>] (asm_do_IRQ+0x4c/0x128)
 r6 = 00000020  r5 = 0000001F  r4 = C01F5588
[<c001fa90>] (asm_do_IRQ+0x0/0x128) from [<c001e804>] (__irq_svc+0x24/0x60)
[<c0034d44>] (release_console_sem+0x0/0x210) from [<c00351e4>] (vprintk+0x290/0x
2e8)
 r8 = 00000051  r7 = C01F6F42  r6 = 00208000  r5 = C3EC3DC8
 r4 = C01F6EF4
[<c0034f54>] (vprintk+0x0/0x2e8) from [<c0035258>] (printk+0x1c/0x20)
[<c003523c>] (printk+0x0/0x20) from [<c00c7324>] (jffs2_lookup_node_frag+0x64/0x
13c)
 r3 = C3EBE7AC  r2 = 00208000  r1 = 00207000  r0 = C019A218
[<c00c72c0>] (jffs2_lookup_node_frag+0x0/0x13c) from [<c00ca970>] (jffs2_add_ful
l_dnode_to_inode+0xac/0x660)
 r6 = C3EBE790  r5 = C3E6BD70  r4 = 00000000
[<c00ca8c4>] (jffs2_add_full_dnode_to_inode+0x0/0x660) from [<c00cb2cc>] (jffs2_
do_read_inode_internal+0x178/0x8d4)
[<c00cb154>] (jffs2_do_read_inode_internal+0x0/0x8d4) from [<c00cba90>] (jffs2_d
o_crccheck_inode+0x68/0xbc)
[<c00cba28>] (jffs2_do_crccheck_inode+0x0/0xbc) from [<c00d32b8>] (jffs2_garbage
_collect_pass+0x1c8/0x840)
 r6 = C3C11200  r5 = C3EC2000  r4 = C03FFC98
[<c00d30f0>] (jffs2_garbage_collect_pass+0x0/0x840) from [<c00d5400>] (jffs2_gar
bage_collect_thread+0x14c/0x18c)
[<c00d52b4>] (jffs2_garbage_collect_thread+0x0/0x18c) from [<c00367d0>] (do_exit
+0x0/0xb24)
 r6 = 00000000  r5 = 00000000  r4 = 00000000


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